Superfluorescence from Lead Halide Perovskite Quantum Dot Superlattices

TL;DR

This paper reports the observation of superfluorescence in lead halide perovskite quantum dot superlattices, demonstrating collective quantum effects in colloidal nanocrystals for the first time, with potential applications in quantum optics.

Contribution

It introduces a novel system of CsPbX3 perovskite nanocrystal superlattices exhibiting superfluorescence, overcoming previous limitations in colloidal nanocrystals.

Findings

Red-shifted emission with accelerated radiative decay

Extended coherence time by over four times

Observation of photon bunching and delayed emission pulses

Abstract

An ensemble of emitters can behave significantly different from its individual constituents when interacting coherently via a common light field. After excitation, collective coupling gives rise to an intriguing many-body quantum phenomenon, resulting in short, intense bursts of light: so-called superfluorescence. Because it requires a fine balance of interaction between the emitters and their decoupling from the environment, together with close identity of the individual emitters, superfluorescence has thus far been observed only in a limited number of systems, such as atomic and molecular gases and semiconductor crystals, and could not be harnessed for applications. For colloidal nanocrystals, however, which are of increasing relevance in a number of opto-electronic applications, the generation of superfluorescent light was precluded by inhomogeneous emission broadening, low oscillator strength, and fast exciton dephasing. Using caesium lead halide (CsPbX3, X = Cl, Br) perovskite nanocrystals that are self-organized into highly ordered three-dimensional superlattices allows us to observe key signatures of superfluorescence: red-shifted emission with more than ten-fold accelerated radiative decay, extension of the first-order coherence time by more than a factor of four, photon bunching, and delayed emission pulses with Burnham-Chiao ringing behaviour at high excitation density. These mesoscopically extended coherent states can be employed to boost opto-electronic device performances and enable entangled multi-photon quantum light sources.